{"id":"CVE-2026-98584","summary":"net/sched: fix potential stack infoleak in em_text_dump()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix potential stack infoleak in em_text_dump()\n\nem_text_dump() allocates struct tcf_em_text on the stack without zeroing\nit.  strscpy() writes the algorithm name and a NUL terminator into\nconf.algo[], leaving the remaining bytes uninitialised.  nla_put_nohdr()\nthen copies the full struct to the netlink response.\n\nKMSAN on Linux 7.2-rc6 reports two kernel-infoleak splats from this path,\none triggered via \"tc filter show\" and one via a raw RTM_GETTFILTER dump:\n\n  BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x1c9/0x2620\n    nla_put_nohdr+0x83/0x130\n    em_text_dump+0x291/0x550\n  Local variable conf created at: em_text_dump+0x5d/0x550\n  Bytes 168-179 of 199 are uninitialized\n\nI am not certain whether this constitutes a real security problem in\npractice: the test was conducted in a controlled KMSAN environment and\nthe leaked stack bytes may or may not carry sensitive data on actual\nproduction kernels.  I am reporting it because KMSAN flagged it as a\nkernel-infoleak and the fix is straightforward.  I can provide a\nuserspace reproducer on request.\n\nThe original code used strncpy() which zero-pads to the destination size.\nCommit b04202d6065c (\"net/sched: replace strncpy with strscpy\") replaced\nit with strscpy(), which does not pad, creating this condition.\nZero-initialising the struct closes it.","modified":"2026-10-19T02:46:52.964488063Z","published":"2026-10-18T15:18:57.204Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98584.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0b160417826d22f24fc31a5b9cfae3b14aa70f76"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9923e1c537f91f3530b52d4efce85f3d9c131bf8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9c572a83037a7dcd653ba3a9cc468c16b857d0c9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98584.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98584"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b04202d6065cba5dfd51fb9866400b25573eac67"},{"fixed":"9923e1c537f91f3530b52d4efce85f3d9c131bf8"},{"fixed":"0b160417826d22f24fc31a5b9cfae3b14aa70f76"},{"fixed":"9c572a83037a7dcd653ba3a9cc468c16b857d0c9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98584.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98584.json"}}],"schema_version":"1.9.0"}